A steering column allows for the adjustment in depth and/or in height of the steering wheel. Conventionally per se, a steering column comprises a support element intended to be fixed to the chassis of the vehicle, an upper body mounted mobile in the support element, an internal tube mounted in the upper body and a tightening and blocking device the upper body in position on the internal tube. On known adjustable steering columns, the controlling of the tightening and blocking device is carried out by means of a control lever. The control lever makes it possible to place the tightening and blocking device in a locked position wherein the upper body is blocked in position on the internal tube and a unlocked position wherein the adjusting in depth and/or height of the steering column is authorized, as the upper body is no longer blocked in position on the internal tube.
In order to prevent the device for adjusting and blocking from moving during a collision of the vehicle with another vehicle or an obstacle, and consequently the position of the airbag during its deployment from not being provided, a mechanism is provided in steering columns that makes it possible to block the adjusting in depth of the steering column during the impact of the driver on the steering wheel during the collision.
Patent application EP2100795 and EP2100796 relate to steering columns comprising such a blocking mechanism. The blocking mechanism implemented comprises a toothed member cooperating with a notched arrangement provided on the upper body or the support element.
The mechanisms implemented in the steering columns described in the abovementioned documents have however a certain number of disadvantages. In particular, they generate an excessive effort on the control lever, with this excessive effort primarily observed when the toothed member is in contact with the notched arrangement provided on the upper body or the chassis element according to a tooth-on-tooth configuration. The excessive effort on the lever is furthermore sometimes such that it is impossible in certain cases to maneuver the control lever in order to place the device for adjusting and blocking in locked position. Furthermore, the blocking in depth of the upper body is no longer provided in this case.